Hydrocephalus is an excessive accumulation of cerebrospinal fluid (CSF) within the ventricular spaces of the brain. In infants, hydrocephalus enlarges the head; in infants and adults, resulting compression can damage brain tissue. With early detection and surgical intervention, the prognosis improves but remains guarded. Even after surgery, such complications as mental retardation, impaired motor function, and vision loss can persist. Without surgery, the prognosis is poor: Mortality may result from increased intracranial pressure (ICP); infants may also die prematurely of infection and malnutrition.
Hydrocephalus may result from an obstruction in CSF flow (noncommunicating hydrocephalus) or from faulty absorption of CSF (communicating hydrocephalus). (See Normal circulation of CSF.)
In noncommunicating hydrocephalus, the obstruction occurs most frequently between the third and fourth ventricles, at the aqueduct of Sylvius, but it can also occur at the outlets of the fourth ventricle (foramina of Luschka and Magendie) or, rarely, at the foramen of Monro. This obstruction may result from faulty fetal development, infection (syphilis, granulomatous diseases, meningitis), a tumor, cerebral aneurysm, or a blood clot (after intracranial hemorrhage).
In communicating hydrocephalus, faulty absorption of CSF may result from surgery to repair a myelomeningocele, adhesions between meninges at the base of the brain, or meningeal hemorrhage. Rarely, a tumor in the choroid plexus causes overproduction of CSF, producing hydrocephalus.
Hydrocephalus occurs most commonly in neonates but can also occur in adults as a result of injury or disease. It affects 1 of every 1,000 people.
In infants, the unmistakable sign of hydrocephalus is rapidly increasing head circumference, clearly disproportionate to the infant’s growth. Other characteristic changes include widening and bulging of the fontanels; distended scalp veins; thin, shiny, and fragile-looking scalp skin; and underdeveloped neck muscles. (See Signs of hydrocephalus.) In severe hydrocephalus, the roof of the orbit is depressed, the eyes are displaced downward, and the sclerae are prominent. Sclera seen above the iris is called the “setting-sun sign.” A high-pitched, shrill cry, abnormal muscle tone of the legs, irritability, anorexia, and projectile vomiting commonly occur. In adults and older children, indicators of hydrocephalus include decreased level of consciousness (LOC), ataxia, incontinence, and impaired intellect.
In infants, abnormally large head size for the patient’s age strongly suggests hydrocephalus. Measurement of head circumference is a most important diagnostic technique. Skull X-rays show thinning of the skull with separation of sutures and widening of fontanels.
Other diagnostic tests for hydrocephalus, including arteriography, computed tomography scan, and magnetic resonance imaging, can differentiate between hydrocephalus and intracranial lesions and can also demonstrate the Arnold-Chiari deformity, which may occur in an infant with hydrocephalus. (See Arnold-Chiari syndrome.)
Surgical correction is the only treatment for hydrocephalus. Surgery typically consists of insertion of a ventriculoperitoneal shunt, which transports excess fluid from the lateral ventricle into the peritoneal cavity. A less common procedure is insertion of a ventriculoatrial shunt, which drains fluid from the brain’s lateral ventricle into the right atrium of the heart, where the fluid makes its way into the venous circulation.
Complications of surgery include shunt infection, septicemia (after ventriculoatrial shunt), adhesions and paralytic ileus, migration, peritonitis, and intestinal perforation (with peritoneal shunt).
On initial assessment, obtain a complete history from the patient or his family. Note general behavior, especially irritability, apathy, or decreased LOC. Perform a neurologic assessment. Examine the eyes: pupils should be equal and reactive to light. In adults and older children, evaluate movements and motor strength in extremities. Watch especially for ataxia, confusion, and incontinence. Ask the patient if he has headaches, and watch for projectile vomiting; both are signs of increased ICP. Also watch for seizures. Note changes in vital signs.
Before surgery to insert a shunt:
❑Encourage maternal-infant bonding when possible. When caring for the infant yourself, hold him on your lap for feeding; stroke and cuddle him, and speak soothingly.
❑Check fontanels for tension or fullness, and measure and record head circumference. On the patient’s chart, draw a picture showing where to measure the head so that other staff members measure it in the same place, or mark the forehead with ink.
❑To prevent postfeeding aspiration and hypostatic pneumonia, place the infant on his side and reposition every 2 hours, or prop him up in an infant seat.
❑To prevent skin breakdown, make sure his earlobe is flat, and place a sheepskin or rubber foam under his head.
❑When turning the infant, move his head, neck, and shoulders with his body to reduce strain on his neck.
❑Feed the infant slowly. To lessen strain from the weight of the infant’s head on your arm while holding him during feeding, place his head, neck, and shoulders on a pillow.
After surgery:
❑Place the infant on the side opposite the operative site with his head level with his body unless the physician’s orders specify otherwise.
❑Check temperature, pulse rate, blood pressure, and LOC. Also check fontanels for fullness daily. Watch for vomiting, which may be an early sign of increased ICP and shunt malfunction.
❑Watch for signs of infection, especially meningitis: fever, stiff neck, irritability, or tense fontanels. Also watch for redness, swelling, or other signs of local infection over the shunt tract. Check dressing often for drainage.
❑Listen for bowel sounds after ventriculoperitoneal shunt.
❑Check the infant’s growth and development periodically, and help the parents set goals consistent with ability and potential. Help parents focus on their child’s strengths, not his weaknesses. Discuss special education programs, and emphasize the infant’s need for sensory stimulation appropriate for his age. Teach parents to watch for signs of shunt malfunction, infection, and paralytic ileus. Tell them that surgery for lengthening the shunt will be required periodically as the child grows older. Surgery may also be required to correct shunt malfunctioning or to treat infection. Emphasize that hydrocephalus is a lifelong problem and that the child will require regular, continuing evaluation.
Review other book chapters online related to Hydrocephalus:
Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Professional Guide to Diseases (Eighth Edition) Authors: Springhouse Publisher: Lippincott Williams & Wilkins Copyright: 2005 ISBN: 1-58255-370-X 
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